| Brachygastra lecheguana | |
|---|---|
 | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Family: | Vespidae |
| Subfamily: | Polistinae |
| Tribe: | Epiponini |
| Genus: | Brachygastra |
| Species: | B. lecheguana |
| Binomial name | |
| Brachygastra lecheguana | |
| Synonyms[1] | |
| |
Brachygastra lecheguana (Latreille 1824), formerly known asNectarina lecheguana,[2] is a species of darkpaper wasp[3] found across North and South America.[2] It nests in underbrush in grassland-type environments, and produceshoney, characteristic of thegenusBrachygastra.[2]
Common names include marimbondo-do-campo, marimbondo-do-pasto,[4] marimbondo-exu, marimbondo-de-pote, marimbondo-de-purrão, and avispa-de-pote,[5] among others depending on the location.
It is calledtu in theKwaza language ofRondônia, Brazil.[6]
B. lecheguana belongs to theEpiponini tribe ofPolistinae wasps,[7] sometimes referred to as Polybiinae wasps.[2][7] It is a Neotropical social wasp species that falls under the genusBrachygastra.[7]
Brachygastra wasps are identified, as noted in Andena and Carpenter (2012), by an anatomical projection over their posterior. Thescutellum,metanotum, andpropodeum, three of thehymenopteran back structures, combined form a flat, vertical surface in the middle of the body (mesosoma).[8]
B. lecheguana is very closely related toB. mellifica andB. borellii,[8] and indeed some authors suggest thatB. lecheguana andB. mellifica can only be differentiated based on where they are found with respect to their reported distribution throughout the Americas.[2] However, there are morphological and genetic differences between these species.[8][9][10]
Brachygastra lecheguana was first described byPierre André Latreille in 1824.[2] It was originally namedNectarina lecheguana,[2] and the switch fromNectarina toBrachygastra as a name for this genus was not standard in the scientific literature until the 1940s.[8] Between 1824 and 1943, this species was documented as a member of the following genera:Polistes,Vespa,Nectarinia (a misspelling ofNectarina, and a misuse of this genus of birds),Brachygaster (another misspelling, and a misuse of this genus of parasitic wasp),Melissaia, andCaba.[2][8]
In 1923, Bequeart performed a survey of the literature on this species, compiling accounts and descriptions by entomologistsFerdinand de Saussure,Hermann von Ihering, anddu Buysson among numerous others, creating a source of descriptive information on this species.[2] One study has focused on the morphological caste differentiation ofB. lecheguana[11] and another directly studied itsforaging behavior.[3] While not the focus,B. lecheguana has been included in studies of groups of wasps known to benatural enemies of agricultural pests,[12][13][14] and has been documented in a number of papers cataloging flower visitation by insects and birds.[15][16]
Bequaert provides a detailed description of the anatomy and features ofB. lecheguana.[2] This species is black, with an abdomen colored with yellow stripes, having patches on thethorax and head colored yellow as well.[4] The abdomen is wide and truncate,[8] and nests are globular,[4] gray, and close to the ground.[2] Queens and workers were recorded to be ~7.5–9 mm long and males ranged from ~7.5–8 mm in length.[2]B. lecheguana can be differentiated fromB. mellifica based on the male reproductive anatomy; inB. lecheguana the males have an apically wide digitus while that ofB. mellifica males is relatively narrow.[8]
B. lecheguana is found across North and South America, ranging fromMexico toArgentina. This species has been observed a couple times as far north asTexas andArizona, but tends to be rare north of Mexico.[2]
Nests are oval, about the size of a human head, made of gray paper-like material, and close to the ground.[2] Bequeart includes a lengthy description of the construction process for one of these nests in his 1932 publication on Polybiinae wasps.[2] Nests are located in undergrowth,[4] and it appears that these wasps prefer moretemperate locations characterized by open, less humid, grassland environments.[15][17][18]
As a member of the polistine wasp tribeEpiponini,B. lecheguana is aswarm-founding species.[7] Their nests arepolygynous,[7] with reproductively active females numbering anywhere from 1%[11] to possibly even 17% of a colony.[19] Reports of the total number of individuals in a given colony have been recorded by a couple different sources ranging from 13800[11] to 15000,[2] although it appears that a limited number of colony counts are documented in the scientific literature. The male to female ratio was reported as 0 in a colony collected in May,[11] 1:15 in a colony collected in January, and 1:1 in a colony observed in the fall.[2]
Nests are recorded to beperennial, often lasting several years.[2] Newcolonies are formed in the spring when several fertile queens, accompanied by a few worker wasps in a swarm, establish new nest sites.[2]
In a study that characterized the morphological difference between differentcastes inB. lecheguana, researchers usedovary development to classify individuals as workers, queens, or "intermediates". Workers had either undeveloped or slightly developed ovaries, and constituted around 39% of the study's pool of individuals, while queens, with well developed ovaries containing 6-12oocytes, accounted for around 0.7% of the individuals. A third group, with moderately developed ovaries containing 1-5 oocytes, was identified as an intermediate caste and accounted for around 60.3% of the colony. While the ovaries belonging to queen individuals had evidence ofinsemination, there was no detectablesperm in the reproductive organs of the intermediate individuals.[11]
Anecdotal accounts ofB. lecheguana nests suggest that queens are larger than workers.[2] However it appears that a more careful statistical analysis indicates that there is no overall size difference between queens, workers, or intermediates.[11] There is no difference in overall size, but the queens have a set of anatomical proportions distinct from the intermediates and workers, smaller in some structures and larger in others.[11]
While it appears that caste might be discernible through ovary development,[11] the absence of morphological differences between individuals inB. lecheguana suggests that there is no meaningful morphological caste.[7] However it is clear that individuals can be designated reproductives and nonreproductives.[7]
Bequaert describes the extensive color and shape similarities betweenB. lecheguana and a number of other species with the word "homeochromic" instead of "mimic". He lists a number ofvespid wasps andpotter wasps belonging to the generaPachodynerus,Odynerus, andAncistrocerus, and severalcrabronid wasps of the generaGorytes andCerceris. Along with wasps, there are several bee species that are homeochromic, includingmason bees of the generaMegachile,Anthidiellum,Hypanthidium,Dianthidium, and the speciesStelis costaricensis,cuckoo bees belonging to the genusEpeolus, stinglessTrigona bees, andsweat bees from the genusHalictus. He also lists asoldier fly of the genusStratiomys as a homeochromic species.[2]
WhileB. lecheguana, Bequaert suggests, is the most abundant in this group of homeochromic species, he does not make the claim that these similarities arose frommimicry in the classic sense, but he suggests that further research would be helpful.[2]
B. lecheguana is known to visit a number of plants to obtainnectar resources.[3] This wasp has been documented visiting the flowers ofBaccharis spp.,[20]Erythrina crista-galli,[21]Ziziphus cotinifolia,Solanum paniculatum,Sidastrum paniculatum, andErythroxylon catingae[15] and more.[2] In addition to obtaining nectar from flowers,B. lecheguana has been reported as a visitor ofextrafloral nectaries on such species asBanisteriopsis malifolia.[3]
This wasp does not rely solely on nectar for food; it is a well-documented predator of a number of differentarthropod species.[22] Among its prey arebeetles of the genusAnthonomus[3][22] and thecoffee leaf minerLeucoptera coffeella.[13] It is known to forage on a number of plant species includingEugenia uniflora fruits,[23]Banisteriopsis malifolia,[3] and several agriculturally relevant plants.[14][24][25]
This species has been documented to compete for food resources with several other animal species.[3][14]B. lecheguana competes with theant speciesCamponotus blandus for the plantBanisteriopsis maliflora, and, consequently, the wasp is typically found on ant-free plants and has been known to interrupt its foraging when an ant approaches.[3] This supports the hypothesis thatB. lecheguana is in a mutualistic relationship with the plantB. maliflora, since the plant supplies nectar reserves to the wasp, and the wasp preys onherbivorous insectlarvae living on the plant.[3]
Another study suggests thatB. lecheguana may also compete withparasitoids for coffeeleaf miner larvae in an agricultural setting.[14]
Although this wasp visits a diverse collection offlowering plants,[2] it is only reported as apollinator in a limited number of instances.B. lecheguana is documented as a pollinator ofBaccharis spp.[20] Additionally, as an alien species to theGalápagos Islands, there have been reports that catalogB. lecheguana as an important pollinator on the island ofSanta Cruz.[16]
The limited information on this species documents very few instances ofparasitism, although it is unlikely that this wasp is free from parasites. One report suggests thatB. lecheguana is subject to parasitism byStrepsiptera.[2]
B. lecheguana is a prey target for a number of animals.[26] ThelizardTupinambis teguixin is known to prey on this wasp, having easy access to its nests since they are low to the ground and easily accessible.[2] A number ofbirds are suspected to prey onB. lecheguana, although there are relatively few documentations of this in the literature.[2][5] Also, the army antEciton dulcius is reported to prey on this wasp.[26] Another source of predation is byasilids, or robber flies.[2]
B. lecheguana is a known natural enemy of the coffee leaf minerLeucoptera coffeella, along with several other species of wasp includingPolistes versicolor,Polybia paulista,[27]Polybia occidentalis,[13]Polybia scutellaris, andProtonectarina sylveirae.[14]B. lecheguana are often used asbiological controls incoffeeplantations in order to prevent the proliferation of the devastating leaf miner.[12] In order to test the effectpesticides have on the environment and to test the efficacy of using pesticides in conjunction with natural predators, the effect that several pesticides have on the health ofB. lecheguana and other wasps was assayed.[12] This wasp species is found to be highly susceptible tochlorpyrifos and otherorganophosphate pesticides.[12] Even at half the recommended dosage of a number of these pesticides, the wasp was found to have nearly 100% mortality.[13]
In addition to coffee plantations, wasps have also been documented to forage incashew farms[24] and inhabiteucalyptus plantations[25] where it may play a role in pest control.
Theaggressiveness of this wasp is disputed.[2][4][5] While some report that the wasp is rather unaggressive even when disturbed,[2] others warn of its aggressive behavior towards human victims.[4][5] Having a moderately painful sting,[28]B. lecheguana uses anautotomous stinging strategy, employing a barbed stinger specialized forvenom delivery and release of the stinger in the sting site.[29]
Some sources indicate that thehoney from theB. lecheguana hives is harvested regularly and consumed.[2] In certain parts of Mexico, it appears thatB. lecheguana is maintained in a state of semi-domestication.[5] It is warned, however, that the honey can also bepoisonous.[5] The toxicity of the honey is a result of the wasp collecting nectar during theDatura blooming season.[2]
Ethnoentomologists andanthropologists have documented use ofB. lecheguana as a medical treatment in certain communities.[30] Some of the communities eat both the honey and the larvae of the wasp,[5] while others use the adult wasps themselves.[30] It appears that the honey has been used to treatcoughing orasthma in the Pankararé andMatinha communities inBrazil.[30] The wasp itself has been used in theSerrinha area to treat pain associated with their stings.[30]